Plantwise Factsheets for Farmers
Coffee Black Twig Borer
Recognize the problem
The coffee black twig borer is an insect pest which is causing a lot of damage in coffee in the Mukono District (Uganda), especially in the dry season. The adult coffee twig borer is a small (1 to 2 mm long) shiny black insect that is oval in shape. The beetle spends much of its life inside the coffee branch and is usually only seen when the branch is broken open.
Female black twig borers tunnel into the current year's twigs, leaving pin-sized entry holes. Once inside they tunnel through the young coffee branches. One to three females is enough to kill the twig or branch.
The first signs of infestation are a yellowing of the leaves on a branch. If this is seen then the branch should be inspected for the tiny entrance holes usually located on the branch underside. A whitish pile of dust can sometimes be seen at each hole.
If no holes are visible then try gently bending the branch to test for weakness. The petiole will break at the point of entry and occasionally a tiny beetle may be seen. Later signs of infestation are a blackening of the stem and leaves from the entrance hole towards the tip of the branch. Wilting of twigs and branches is usually seen within weeks of infestation.
- Pruning and burning of beetle-infested plant material is essential.
- Good tree care will promote vigor and help in resisting infestation or recovering from infestation.
- Spray the whole plant with deltamethrin 12g/l + chlorpyrifos 300g/l, or fenitrothion pesticides. Mix according to the manufacturer’s instructions on the label and apply the following way:
- Spray young coffee plants the first time one year after transplanting, before flowering.
- In older coffee plantations, spray after the desuckering and before flowering.
- Then spray once every 2 weeks, 3 times in total during the season.
When using a pesticide, always wear protective clothing and follow the instructions on the product label, such as dosage, timing of application, and pre-harvest interval.
The recommendations in this factsheet are relevant to:
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